Factor Xa (Last Updated - 2/28/2005)

-makes up the initial step of the common pathway
-formed via activation of Factor X --> this reaction is catalyzed by:
     1) Calcium (Factor IV)
     2) Phospholipids
     3) Factor VIIa
     4) Factor VIIIa
     5) Factor IXa
-Factor Xa (along with calcium (Factor IV), phospholipids & Factor Va) in turn catalyzes the activation of Factor II (Prothrombin) to Factor IIa (Thrombin)

-click here to view an image of the clotting cascade

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References:

Goodman & Gilman's: The Pharmacologic Basis Of Therapeutics - 10th Edition - 2001. Chapter 55.